A Healthy HVAC System is Key to a Healthy Building
The American National Standards Institute (ANSI) for the first time has approved the Associated Air Balance Council’s (AABC) manual for system balance, according to the organization.
This is the seventh edition of the manual. At the highest level, balance essentially refers to a system that is operating as it was designed. Roger Holder, the principal of RD Holder Engineering in Goodyear, AZ, defines balance as “proportional flows in the distribution system (submains, branches, and terminals) according to specified design quantities” and a balanced system as one that is “designed to deliver heat transfer required for occupant comfort or process load at design conditions.”
Keeping these systems running at peak efficiency is a large and growing market. Research and Markets recently released a report that says that the worldwide indoor air quality market will have an compound annual growth rate (CAGR) of 8.3 percent between this year and 2020.
The new manual supersedes one published in 2002. “The key thing obviously is that when you look at overall heating, ventilation and air conditioning system there so many things in the system that if they are not set properly can cause massive amount of energy use,” said Gaylon Richardson, the chairman of the AABC standards committee.
The approach is comprehensive. “It’s really simple,” Richardson said. “The total system balancing process should touch every piece of the HVAC system in the building. It should set the flows correctly and test controllers. It should test the controls sequences and verify the calibration of controllers and do a point verification of the HVAC systems.”
The manual offers new and updated features. Richardson says that a key change is that information is available on a system-by-system basis. There no longer is the need to wade through the entire report for specific pieces of data. There are new sections on testing energy recovery systems and chilled beams, terminal boxes for constant and variable volume air systems, updated sections on constant volume, variable volume air systems, revised recommendations for duct leakage testing and other new and updated content, according to the organization.”
The health of the HVAC system is a vital element of the comfort of a building, its health impacts on occupants and the cost of operations.
At LinkedIn, Darren Witter – the Vice President and General Manager of Melink Test & Balance, which is in Milford, OH – provided some background on air balance, which is essentially the health checkup for the HVAC system.
Many of the problems in a building’s environment – which often cause dissatisfaction among occupants and ultimately cost money – can be traced to poorly functioning HVAC systems. Witter wrote that a building, just like a human being, shows signs of not being well. These often are related to the HVAC system and its functioning. The cause is not necessarily neglect. Indeed, it can be incomplete attempts to keep the system up to date:
When upgrading rooftop units, coils, ductwork, moving diffusers around, etc., Facilities Managers (FM) want to be ensured that their new equipment was properly installed and is going to work as they expect. Unfortunately, it’s not as simple as other replacements, such as changing a light bulb. HVAC equipment replacements must be inspected and tested for proper operation, otherwise the entire facility’s ecosystem could be thrown out of balance.
Witter also points to the importance of adjusting the HVAC system when the floorplan of the building changes.
A post at the site of the Jackson & Sons Heating & Air Conditioning – a firm in Dudley, NC — offers some basics of HVAC health. If there is more air returning through the air handler than coming out of the supply duct, comfort will decrease. Comfort also will decrease if there is insufficient air volume or air pressure. Air balancing, the piece says, can uncover leaking ductwork. Corrective measures, the posts says, including changing the size of the duct work in the affected areas, changing the size of the return registers, installing mechanical dampers inside the duct and fixing leading ducts.
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